北美云杉象鼻虫是危害北美云杉幼林的主要害虫。初春时节,象鼻虫成虫或爬或飞到顶梢上,在树皮下产卵。幼虫钻到顶梢里,把韧皮部吃光,使其死亡。顶梢死去后,下面的轮生侧枝很快形成背地性,并呈直立状。这一过程往往形成树干缺陷,如弯曲、分叉等,影响木材的质量。反复受到危 North American spruce weevil is a major pest that endangers young North American spruce. Early spring, weevil adult or climb or fly to the top, spawn under the bark. The larvae drill to the top, the phloem to eat, to death. After the top dead, the following rotation of the lateral branches quickly formed in the ground, and was erect. This process tends to form trunk defects, such as bending, bifurcation, etc., affecting the quality of the wood. Repeatedly endangered